usart.c

AVR_examples proteus examples

#include "includes.h"
#define USART_C

int usart_putchar(char c)
{
	if (c == '\n')
		usart_putchar('\r');
	while(UCSRA & (1 << 5));   //loop_until_bit_is_set(UCSRA,5);
	UDR = c;
	return 0;

}

void init_usart(void)
{
	// 晶振频率 : 4.0MHz
	// 通信参数: 8 Data, 1 Stop, No Parity 
	// 波特率:
	// UBRRL= 0x0C    19200;
	// UBRRL= 0x19    9600;
	// UBRRL= 0x33    4800;
	// UBRRL= 0x67    2400	
	UCSRB = (1<<RXEN)|(1<<TXEN)|(1<<RXCIE);  //允许发送和接收
	UCSRC = (1<<URSEL)|(1<<UCSZ1)|(1<<UCSZ0); //8位数据位+1位停止位
	UBRRH=0x00; 
	UBRRL=0x19;  
	//sei();
}